/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.sun.org.apache.xml.internal.security.keys.storage;

import java.security.KeyStore;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

import com.sun.org.apache.xml.internal.security.keys.storage.implementations.KeyStoreResolver;
import com.sun.org.apache.xml.internal.security.keys.storage.implementations.SingleCertificateResolver;

/**
 * This class collects customized resolvers for Certificates.
 */
public class StorageResolver {

  /**
   * {@link org.apache.commons.logging} logging facility
   */
  private static java.util.logging.Logger log =
      java.util.logging.Logger.getLogger(StorageResolver.class.getName());

  /**
   * Field storageResolvers
   */
  private List<StorageResolverSpi> storageResolvers = null;

  /**
   * Constructor StorageResolver
   */
  public StorageResolver() {
  }

  /**
   * Constructor StorageResolver
   */
  public StorageResolver(StorageResolverSpi resolver) {
    this.add(resolver);
  }

  /**
   * Method addResolver
   */
  public void add(StorageResolverSpi resolver) {
    if (storageResolvers == null) {
      storageResolvers = new ArrayList<StorageResolverSpi>();
    }
    this.storageResolvers.add(resolver);
  }

  /**
   * Constructor StorageResolver
   */
  public StorageResolver(KeyStore keyStore) {
    this.add(keyStore);
  }

  /**
   * Method addKeyStore
   */
  public void add(KeyStore keyStore) {
    try {
      this.add(new KeyStoreResolver(keyStore));
    } catch (StorageResolverException ex) {
      log.log(java.util.logging.Level.SEVERE, "Could not add KeyStore because of: ", ex);
    }
  }

  /**
   * Constructor StorageResolver
   */
  public StorageResolver(X509Certificate x509certificate) {
    this.add(x509certificate);
  }

  /**
   * Method addCertificate
   */
  public void add(X509Certificate x509certificate) {
    this.add(new SingleCertificateResolver(x509certificate));
  }

  /**
   * Method getIterator
   *
   * @return the iterator for the resolvers.
   */
  public Iterator<Certificate> getIterator() {
    return new StorageResolverIterator(this.storageResolvers.iterator());
  }

  /**
   * Class StorageResolverIterator
   * This iterates over all the Certificates found in all the resolvers.
   */
  static class StorageResolverIterator implements Iterator<Certificate> {

    /**
     * Field resolvers
     */
    Iterator<StorageResolverSpi> resolvers = null;

    /**
     * Field currentResolver
     */
    Iterator<Certificate> currentResolver = null;

    /**
     * Constructor StorageResolverIterator
     */
    public StorageResolverIterator(Iterator<StorageResolverSpi> resolvers) {
      this.resolvers = resolvers;
      currentResolver = findNextResolver();
    }

    /**
     * @inheritDoc
     */
    public boolean hasNext() {
      if (currentResolver == null) {
        return false;
      }

      if (currentResolver.hasNext()) {
        return true;
      }

      currentResolver = findNextResolver();
      return (currentResolver != null);
    }

    /**
     * @inheritDoc
     */
    public Certificate next() {
      if (hasNext()) {
        return currentResolver.next();
      }

      throw new NoSuchElementException();
    }

    /**
     * Method remove
     */
    public void remove() {
      throw new UnsupportedOperationException("Can't remove keys from KeyStore");
    }

    // Find the next storage with at least one element and return its Iterator
    private Iterator<Certificate> findNextResolver() {
      while (resolvers.hasNext()) {
        StorageResolverSpi resolverSpi = resolvers.next();
        Iterator<Certificate> iter = resolverSpi.getIterator();
        if (iter.hasNext()) {
          return iter;
        }
      }

      return null;
    }
  }
}
